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authorDenys Vlasenko2019-05-24 17:03:28 +0200
committerDenys Vlasenko2019-05-24 17:03:28 +0200
commitdff2bd733fc2dac08d34f2cfad0e68aeb8e7a7a2 (patch)
tree0085fabf15b8ca5034636f39e97e9ba306ca7671 /archival/libarchive
parent309f5e3775ed9cc0837c6d93482735bc4f117d5b (diff)
downloadbusybox-dff2bd733fc2dac08d34f2cfad0e68aeb8e7a7a2.zip
busybox-dff2bd733fc2dac08d34f2cfad0e68aeb8e7a7a2.tar.gz
libarchive: treat one "FIXME: avoid seek"
function old new delta xmalloc_read_with_initial_buf - 205 +205 setup_transformer_on_fd 154 150 -4 xmalloc_open_zipped_read_close 143 135 -8 xmalloc_read 201 10 -191 ------------------------------------------------------------------------------ (add/remove: 1/0 grow/shrink: 0/3 up/down: 205/-203) Total: 2 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'archival/libarchive')
-rw-r--r--archival/libarchive/open_transformer.c44
1 files changed, 27 insertions, 17 deletions
diff --git a/archival/libarchive/open_transformer.c b/archival/libarchive/open_transformer.c
index 4a4bf39..97bcc32 100644
--- a/archival/libarchive/open_transformer.c
+++ b/archival/libarchive/open_transformer.c
@@ -159,47 +159,44 @@ void FAST_FUNC fork_transformer(int fd, const char *transform_prog)
*/
static transformer_state_t *setup_transformer_on_fd(int fd, int fail_if_not_compressed)
{
- union {
- uint8_t b[4];
- uint16_t b16[2];
- uint32_t b32[1];
- } magic;
transformer_state_t *xstate;
xstate = xzalloc(sizeof(*xstate));
xstate->src_fd = fd;
- xstate->signature_skipped = 2;
/* .gz and .bz2 both have 2-byte signature, and their
* unpack_XXX_stream wants this header skipped. */
- xread(fd, magic.b16, sizeof(magic.b16[0]));
+ xstate->signature_skipped = 2;
+ xread(fd, xstate->magic.b16, 2);
if (ENABLE_FEATURE_SEAMLESS_GZ
- && magic.b16[0] == GZIP_MAGIC
+ && xstate->magic.b16[0] == GZIP_MAGIC
) {
xstate->xformer = unpack_gz_stream;
USE_FOR_NOMMU(xstate->xformer_prog = "gunzip";)
goto found_magic;
}
if (ENABLE_FEATURE_SEAMLESS_Z
- && magic.b16[0] == COMPRESS_MAGIC
+ && xstate->magic.b16[0] == COMPRESS_MAGIC
) {
xstate->xformer = unpack_Z_stream;
USE_FOR_NOMMU(xstate->xformer_prog = "uncompress";)
goto found_magic;
}
if (ENABLE_FEATURE_SEAMLESS_BZ2
- && magic.b16[0] == BZIP2_MAGIC
+ && xstate->magic.b16[0] == BZIP2_MAGIC
) {
xstate->xformer = unpack_bz2_stream;
USE_FOR_NOMMU(xstate->xformer_prog = "bunzip2";)
goto found_magic;
}
if (ENABLE_FEATURE_SEAMLESS_XZ
- && magic.b16[0] == XZ_MAGIC1
+ && xstate->magic.b16[0] == XZ_MAGIC1
) {
+ uint32_t v32;
xstate->signature_skipped = 6;
- xread(fd, magic.b32, sizeof(magic.b32[0]));
- if (magic.b32[0] == XZ_MAGIC2) {
+ xread(fd, &xstate->magic.b16[1], 4);
+ move_from_unaligned32(v32, &xstate->magic.b16[1]);
+ if (v32 == XZ_MAGIC2) {
xstate->xformer = unpack_xz_stream;
USE_FOR_NOMMU(xstate->xformer_prog = "unxz";)
goto found_magic;
@@ -344,11 +341,24 @@ void* FAST_FUNC xmalloc_open_zipped_read_close(const char *fname, size_t *maxsz_
*maxsz_p = xstate->mem_output_size;
}
} else {
- /* File is not compressed */
-//FIXME: avoid seek
- xlseek(xstate->src_fd, - xstate->signature_skipped, SEEK_CUR);
+ /* File is not compressed.
+ * We already read first few bytes, account for that.
+ * Exmaple where it happens:
+ * "modinfo MODULE.ko" (not compressed)
+ * open("MODULE.ko", O_RDONLY|O_LARGEFILE) = 4
+ * read(4, "\177E", 2) = 2
+ * fstat64(4, ...)
+ * mmap(...)
+ * read(4, "LF\2\1\1\0\0\0\0"...
+ * ...and we avoided seeking on the fd! :)
+ */
xstate->signature_skipped = 0;
- image = xmalloc_read(xstate->src_fd, maxsz_p);
+ image = xmalloc_read_with_initial_buf(
+ xstate->src_fd,
+ maxsz_p,
+ xmemdup(&xstate->magic, xstate->signature_skipped),
+ xstate->signature_skipped
+ );
}
if (!image)